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[PATCH master/7.12] Throw error when ptrace fail in regsets_fetch_inferior_registers
- From: Yao Qi <qiyaoltc at gmail dot com>
- To: gdb-patches at sourceware dot org
- Date: Wed, 3 Aug 2016 14:19:39 +0100
- Subject: [PATCH master/7.12] Throw error when ptrace fail in regsets_fetch_inferior_registers
- Authentication-results: sourceware.org; auth=none
When I run process-dies-while-detaching.exp with GDBserver, I see many
warnings printed by GDBserver,
ptrace(regsets_fetch_inferior_registers) PID=26183: No such process
ptrace(regsets_fetch_inferior_registers) PID=26183: No such process
ptrace(regsets_fetch_inferior_registers) PID=26184: No such process
ptrace(regsets_fetch_inferior_registers) PID=26184: No such process
regsets_fetch_inferior_registers is called when GDBserver resumes each
lwp.
#2 0x0000000000428260 in regsets_fetch_inferior_registers (regsets_info=0x4690d0 <aarch64_regsets_info>, regcache=0x31832020)
at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/linux-low.c:5412
#3 0x00000000004070e8 in get_thread_regcache (thread=0x31832940, fetch=fetch@entry=1) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/regcache.c:58
#4 0x0000000000429c40 in linux_resume_one_lwp_throw (info=<optimized out>, signal=0, step=0, lwp=0x31832830)
at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/linux-low.c:4463
#5 linux_resume_one_lwp (lwp=0x31832830, step=<optimized out>, signal=<optimized out>, info=<optimized out>)
at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/linux-low.c:4573
The is the case that threads are disappeared when GDB/GDBserver resumes
them. Our fix nowadays is to throw exception, caller
linux_resume_one_lwp catches the exception, and swallow it if the lwp
is gone. See linux-low.c:linux_resume_one_lwp. So this patch fixes
the problem by throwing exception in regsets_fetch_inferior_registers.
Another caller of regsets_fetch_inferior_registers, linux_fetch_registers,
needs to catch the exception the same way as linux_resume_one_lwp does.
gdb/gdbserver:
2016-08-02 Yao Qi <yao.qi@linaro.org>
* linux-low.c (regsets_fetch_inferior_registers): Throw
exception on ptrace fail.
(linux_fetch_registers): Rename to ...
(linux_fetch_registers_throw): ... it.
(linux_fetch_registers): Call linux_fetch_registers_throw
and catch the exception. If check_ptrace_stopped_lwp_gone
is false, throw it again.
---
gdb/gdbserver/linux-low.c | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index e251ac4..c72b78c 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -5410,7 +5410,7 @@ regsets_fetch_inferior_registers (struct regsets_info *regsets_info,
char s[256];
sprintf (s, "ptrace(regsets_fetch_inferior_registers) PID=%d",
pid);
- perror (s);
+ perror_with_name (_(s));
}
}
else
@@ -5702,7 +5702,7 @@ usr_store_inferior_registers (const struct regs_info *regs_info,
static void
-linux_fetch_registers (struct regcache *regcache, int regno)
+linux_fetch_registers_throw (struct regcache *regcache, int regno)
{
int use_regsets;
int all = 0;
@@ -5735,6 +5735,23 @@ linux_fetch_registers (struct regcache *regcache, int regno)
}
static void
+linux_fetch_registers (struct regcache *regcache, int regno)
+{
+ TRY
+ {
+ linux_fetch_registers_throw (regcache, regno);
+ }
+ CATCH (ex, RETURN_MASK_ERROR)
+ {
+ struct lwp_info *lwp = get_thread_lwp (current_thread);
+
+ if (!check_ptrace_stopped_lwp_gone (lwp))
+ throw_exception (ex);
+ }
+ END_CATCH
+}
+
+static void
linux_store_registers (struct regcache *regcache, int regno)
{
int use_regsets;
--
1.9.1